scholarly journals A High-Resolution Electric Current Sensor Employing a Piezoelectric Drum Transducer

Micromachines ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1166
Author(s):  
Wei He
Keyword(s):  
High Resolution ◽  
High Sensitivity ◽  
Load Resistance ◽  
Power Grids ◽  
Current Sensing ◽  
Optimal Load ◽  
Power Frequency ◽  
Field Bias ◽  
Low Costs ◽  
Frequency Current

A high-resolution sensor using a piezoelectric drum transducer is proposed for power frequency current sensing (50 Hz or 60 Hz). The utilization of the magnetic circuit helps to enhance the response to the electric currents in the power cords. The high sensitivity of the sensor originates from the superposition of the Ampere forces and the amplified piezoelectric effect of the drum transducer. The feasibility of the sensor was verified by experiments. The device exhibits a broad 3 dB bandwidth of 67.4 Hz without an additional magnetic field bias. The average sensitivity is 31.34 mV/A with a high linearity of 0.49%, and the resolution of the sensor attains 0.02 A. The resolution is much higher than that of the previous piezoelectric heterostructure for two-wire power-cords. Error analysis shows that the uncertainty reaches 0.01865 mV at the current of 2.5 A. Meanwhile, the device can generate a load power of 447.9 nW with an optimal load resistance of 55 KΩ at 10A (f = 50 Hz) in energy harvesting experiments. The features of high sensitivity, excellent linearity, high resolution, low costs, and convenient installation demonstrate the application prospect of the proposed device for measuring power frequency currents in electric power grids.

A high-resolution electric field sensor based on piezoelectric bimorph composite

2021 ◽  
Author(s):  
Miaomiao Cheng ◽  
Jingen Wu ◽  
mengmeng Guan ◽  
Qi Mao ◽  
dan Xian ◽  
...  
Keyword(s):  
High Resolution ◽  
Electric Field ◽  
Electric Fields ◽  
Low Cost ◽  
Rapid Development ◽  
High Sensitivity ◽  
Pdms Layer ◽  
Electric Field Sensor ◽  
Power Frequency ◽  
Field Sensor

Abstract The rapid development of the internet of things (IOT) technology has led to great demand for intelligent electric field sensor (EFS). Several working principles have been proposed, however major challenges remain existed for the requirements of EFS with low-cost, large-range, and high-resolution. In this paper, an EFS based on piezoelectric bending effect using d31 mode is developed, where a bending strain is induced on the sandwiched bimorph structure of PZT/PDMS/PZT under an applied electric field, and the capacitance value of the PDMS layer reveals detectable variation. We demonstrate an electric field sensor operating at the stress-mediated coupling between piezoelectric ceramic and elastic dielectric polymer, which reveals advantages such as simple fabrication process, low-cost and low power consumption. Due to the sandwiched bimorph structure, the strain caused by the electric field can be effectively transferred to improve the resolution of the device. The constitutive equations for the sandwiched bimorph structure are built, and the working principle of the proposed EFS is demonstrated. The EFS exhibits high sensitivity under both AC and DC electric fields, with a resolution of 0.1V/cm in the range of -3 to 3kV/cm. The proposed sensor provides an alternative solution for power equipment fault diagnosis, power frequency electric field detection, etc.

scholarly journals A Multi-Mode Broadband Vibration Energy Harvester Based on MEMS 3D Coils

2021 ◽  
Author(s):  
Hanxiao Wu ◽  
Zhi Tao ◽  
Haiwang Li ◽  
Tiantong Xu ◽  
Wenbin Wang ◽  
...  
Keyword(s):  
Output Power ◽  
Energy Harvester ◽  
Load Resistance ◽  
Vibration Energy ◽  
Vibration Energy Harvester ◽  
Copper Electroplating ◽  
Optimal Load ◽  
Power Frequency ◽  
Half Power ◽  
Multi Mode

This paper presents an electromagnetic vibration energy harvester utilizing 3D MEMS coils and multi-mode structure to improve the output power and broaden the frequency band. We fabricated and assembled the prototype, with a pair of 3D coils fabricated by lithography, silicon etching, silicon direct bonding and copper electroplating, et al., which are compatible with CMOS processes. The numerical simulation was conducted to analysis the vibration modes of the spring-mass system, which revealed the multi-mode mechanism of serpentine springs. We also tested the output power-frequency curves for different load and excitation acceleration to investigate the optimal load resistance and the influence of excitation. The test results showed that the proposed prototype can generate 1.2μW power under 992Hz for 1g acceleration with a half-power bandwidth of 65Hz, which are higher than some recent published data, proving the superiority of proposed structure.

Backscattered Electron Imaging of GaAs/AlGaAs Super Lattice Structures with an Ultra-High- Resolution SEM

1988 ◽  
Vol 46 ◽  
pp. 204-205
Author(s):  
Kazumichi Ogura ◽  
Michael M. Kersker
Keyword(s):  
High Resolution ◽  
Layer Structure ◽  
High Sensitivity ◽  
Beam Current ◽  
Electron Beam Current ◽  
Lattice Structures ◽  
Super Lattice ◽  
Different Types ◽  
Backscattered Electron ◽  
Electron Imaging

Backscattered electron (BE) images of GaAs/AlGaAs super lattice structures were observed with an ultra high resolution (UHR) SEM JSM-890 with an ultra high sensitivity BE detector. Three different types of super lattice structures of GaAs/AlGaAs were examined. Each GaAs/AlGaAs wafer was cleaved by a razor after it was heated for approximately 1 minute and its crosssectional plane was observed.First, a multi-layer structure of GaAs (100nm)/AlGaAs (lOOnm) where A1 content was successively changed from 0.4 to 0.03 was observed. Figures 1 (a) and (b) are BE images taken at an accelerating voltage of 15kV with an electron beam current of 20pA. Figure 1 (c) is a sketch of this multi-layer structure corresponding to the BE images. The various layers are clearly observed. The differences in A1 content between A1 0.35 Ga 0.65 As, A1 0.4 Ga 0.6 As, and A1 0.31 Ga 0.69 As were clearly observed in the contrast of the BE image.

scholarly journals Load Resistance Optimization of Bi-Stable Electromagnetic Energy Harvester Based on Harmonic Balance

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1505
Author(s):  
Sungryong Bae ◽  
Pilkee Kim
Keyword(s):  
External Load ◽  
Harmonic Balance ◽  
Energy Harvester ◽  
Load Resistance ◽  
Electromagnetic Energy ◽  
Analytic Approach ◽  
Accurate Estimation ◽  
Vibration Source ◽  
Optimal Load ◽  
Matching Techniques

In this study, a semi-analytic approach to optimizing the external load resistance of a bi-stable electromagnetic energy harvester is presented based on the harmonic balance method. The harmonic balance analyses for the primary harmonic (period-1T) and two subharmonic (period-3T and 5T) interwell motions of the energy harvester are performed with the Fourier series solutions of the individual motions determined by spectral analyses. For each motion, an optimization problem for maximizing the output power of the energy harvester is formulated based on the harmonic balance solutions and then solved to estimate the optimal external load resistance. The results of a parametric study show that the optimal load resistance significantly depends on the inductive reactance and internal resistance of a solenoid coil––the higher the oscillation frequency of an interwell motion (or the larger the inductance of the coil) is, the larger the optimal load resistance. In particular, when the frequency of the ambient vibration source is relatively high, the non-linear dynamic characteristics of an interwell motion should be considered in the optimization process of the electromagnetic energy harvester. Compared with conventional resistance-matching techniques, the proposed semi-analytic approach could provide a more accurate estimation of the external load resistance.

scholarly journals Load Resistance Optimization of a Broadband Bistable Piezoelectric Energy Harvester for Primary Harmonic and Subharmonic Behaviors

2021 ◽  
Vol 13 (5) ◽  
pp. 2865 ◽  
Author(s):  
Sungryong Bae ◽  
Pilkee Kim
Keyword(s):  
Energy Harvester ◽  
Load Resistance ◽  
Oscillation Period ◽  
Ambient Vibration ◽  
Ambient Vibrations ◽  
Frequency Dependency ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Optimal Load ◽  
Bistable Energy Harvester

In this study, optimization of the external load resistance of a piezoelectric bistable energy harvester was performed for primary harmonic (period-1T) and subharmonic (period-3T) interwell motions. The analytical expression of the optimal load resistance was derived, based on the spectral analyses of the interwell motions, and evaluated. The analytical results are in excellent agreement with the numerical ones. A parametric study shows that the optimal load resistance depended on the forcing frequency, but not the intensity of the ambient vibration. Additionally, it was found that the optimal resistance for the period-3T interwell motion tended to be approximately three times larger than that for the period-1T interwell motion, which means that the optimal resistance was directly affected by the oscillation frequency (or oscillation period) of the motion rather than the forcing frequency. For broadband energy harvesting applications, the subharmonic interwell motion is also useful, in addition to the primary harmonic interwell motion. In designing such piezoelectric bistable energy harvesters, the frequency dependency of the optimal load resistance should be considered properly depending on ambient vibrations.

High Resolution and High Sensitivity Measurement of Methane at 1.51 μm

2006 ◽  
Vol 23 (9) ◽  
pp. 2415-2417
Author(s):  
Deng Lun-Hua ◽  
Gao Xiao-Ming ◽  
Cao Zhen-Song ◽  
Zhao Wei-Xiong ◽  
Zhang Wei-Jun
Keyword(s):  
High Resolution ◽  
High Sensitivity ◽  
Sensitivity Measurement
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